Wiring board, surface light emitting device, and methods for manufacturing the same

Abstract

To provide a wiring board which suppresses increase in kinds of members on a double-sided board, and can reduce manufacturing time and the number of processes.SOLUTION: A method for manufacturing a wiring board includes steps of: preparing a substrate 30 having an insulation resin 10 and a metal member 20 where a rustproof layer 21 is formed on a surface arranged opposite to a second surface 10B of the insulation resin 10; emitting a first laser beam L1 from a first surface 10A side of the insulation resin 10, and forming a bottomed hole 51 which penetrates through the insulation resin 10 and has the surface on the insulation resin 10 side in the metal member 20 as an inner bottom surface 51B; removing a rustproof layer 21 formed on the surface of the metal member 20 in the inner bottom surface 51B of the bottomed hole 51; injecting a conductive paste 40 into the bottomed hole 51, and coating a first surface 10A of the insulation resin 10 with a conductive paste 40 so as to become wiring continuous to the injected conductive paste 40; and curing the conductive paste.SELECTED DRAWING: Figure 2B

Description

[Technical Field]

[0001] The present disclosure relates to a wiring substrate, a light emitting device, and a method for manufacturing the same. [Background technology]

[0002] Vias filled with conductive paste are sometimes used as interlayer wiring in multilayer wiring boards. For example, Patent Document 1 describes a double-sided wiring board having copper foil wiring on both sides of the board and using vias filled with conductive paste as interlayer wiring. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-210514 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of an embodiment of the present disclosure is to provide a wiring board, a light emitting device, and a method for manufacturing the same that can reduce the manufacturing time and the number of steps. [Means for solving the problem]

[0005] A method for manufacturing a wiring board disclosed in an embodiment includes the steps of: preparing a substrate having an insulating resin having a first surface and a second surface opposite to the first surface; and a metal member having an anti-rust layer formed on its surface, arranged facing the second surface of the insulating resin; irradiating a first laser beam from the first surface side of the insulating resin to penetrate the insulating resin and form a bottomed hole whose inner bottom surface is the surface of the metal member facing the insulating resin; removing the anti-rust layer formed on the surface of the metal member at the inner bottom surface of the bottomed hole; injecting a conductive paste into the bottomed hole and applying the conductive paste to the first surface of the insulating resin so as to form a wiring continuous with the injected conductive paste; and hardening the conductive paste.

[0006] In addition, the method for manufacturing a surface light emitting device disclosed in the embodiment includes the steps of manufacturing a wiring board by the method for manufacturing a wiring board disclosed in the embodiment, arranging a light source including a light emitting element on the metal member of the wiring board, arranging a light reflecting member to cover the metal member, and arranging a first light guiding member to cover the light reflecting member.

[0007] In addition, a method for manufacturing a surface light emitting device disclosed in the embodiment includes the steps of manufacturing a wiring board by the method for manufacturing a wiring board disclosed in the embodiment, arranging a light reflecting member so as to cover the first surface of the insulating resin and the conductive paste on the wiring board, arranging a light source including a light emitting element on the first surface side of the insulating resin, arranging a light guiding member so as to cover the light source and the light reflecting member, and arranging a light adjustment member at a position overlapping the light source on the surface of the light guiding member in a planar view.

[0008] In addition, the wiring board disclosed in the embodiment comprises a substrate having an insulating resin having a first surface and a second surface opposite to the first surface, and a metal member arranged facing the second surface of the insulating resin and having an anti-rust layer formed on the surface on the second surface side, and a conductive paste arranged on the substrate, wherein the substrate has a bottomed hole that penetrates the insulating resin and has an inner bottom surface that is the surface of the metal member facing the insulating resin, the inner bottom surface of the bottomed hole has an area where the anti-rust layer has been removed, and the conductive paste is located inside the bottomed hole so as to face the area where the anti-rust layer has been removed, and is arranged on the first surface of the insulating resin so as to form a wiring that is continuous with the conductive paste located inside the bottomed hole.

[0009] In addition, the surface light emitting device disclosed in the embodiment includes a wiring substrate disclosed in the embodiment, a light source including a light emitting element arranged on the metal member of the wiring substrate, a light reflecting member covering the metal member, and a first light guiding member covering the light reflecting member.

[0010] In addition, the surface light emitting device disclosed in the embodiment includes a wiring board disclosed in the embodiment, a light reflecting member covering the first surface of the insulating resin on the wiring board and the conductive paste, a light source including a light emitting element arranged on the first surface side of the insulating resin, a light guiding member covering the light source and the light reflecting member, and a light adjustment member arranged in a position overlapping the light source on the surface of the light guiding member in a planar view. [Effects of the Invention]

[0011] According to the embodiments of the present disclosure, it is possible to provide a wiring board, a light emitting device, and a method for manufacturing the same, which can suppress an increase in the number of types of components in a double-sided board and reduce the manufacturing time and number of steps. [Brief explanation of the drawings]

[0012] [Figure 1A] 3 is a schematic perspective view of a second surface side illustrating a part of a wiring board according to an embodiment. FIG. [Figure 1B]2 is a schematic perspective view of a first surface side illustrating a part of a wiring board according to an embodiment. FIG. [Figure 1C] 3 is a schematic plan view of a second surface side illustrating a part of the wiring board according to the embodiment. FIG. [Figure 1D] 2 is a schematic plan view of a first surface side illustrating a part of the wiring board according to the embodiment. FIG. [Figure 2A] 3 is a schematic plan view of the first surface side illustrating a via connection portion according to the embodiment. FIG. [Figure 2B] 2B is a schematic cross-sectional view illustrating a cross section taken along line IIB-IIB in FIG. 2A. [Figure 2C] 10 is a schematic plan view of the first surface side showing another example of a via connection portion according to the embodiment. FIG. [Figure 3] 1 is a flowchart illustrating a method for manufacturing a wiring board according to an embodiment. [Figure 4A] 3A to 3C are schematic cross-sectional views illustrating examples of substrates prepared in a method for manufacturing a wiring substrate according to an embodiment. [Figure 4B] 5A and 5B are schematic cross-sectional views illustrating a state in which a wiring pattern of a metal member is formed in the method for manufacturing a wiring board according to the embodiment. [Figure 4C] 10A and 10B are schematic cross-sectional views illustrating a state in which a bottomed hole is formed in the method for manufacturing a wiring board according to the embodiment. [Figure 4D] 10 is a schematic cross-sectional view illustrating a state in which a portion of the anticorrosive layer has been removed in the method for manufacturing a wiring board according to the embodiment. FIG. [Figure 4E] 4A and 4B are schematic cross-sectional views illustrating a state in which a conductive paste is applied in the method for manufacturing a wiring board according to the embodiment. [Figure 4F] 4A and 4B are schematic cross-sectional views illustrating a state in which the conductive paste is hardened in the method for manufacturing a wiring board according to the embodiment. [Figure 5A] 10 is a schematic plan view illustrating a part of a mask used to place a conductive paste in the method for manufacturing a wiring board according to the embodiment; FIG. [Figure 5B] 10A and 10B are schematic plan views illustrating some of modified examples of masks used to place conductive paste in the method for manufacturing a wiring board according to the embodiment. [Figure 5C] 10A and 10B are schematic plan views illustrating a part of another modified example of a mask used to place a conductive paste in the method for manufacturing a wiring board according to the embodiment. [Figure 5D] 10A and 10B are schematic plan views illustrating a part of another modified example of a mask used to place a conductive paste in the method for manufacturing a wiring board according to the embodiment. [Figure 6A] 1 is a schematic plan view illustrating the surface light emitting device according to the first and second embodiments. [Figure 6B] FIG. 6B is a schematic plan view illustrating an enlarged portion of FIG. 6A. [Figure 6C] 2 is a schematic plan view illustrating a part of a wiring substrate in the surface light emitting device according to the first embodiment. FIG. [Figure 7] 7 is a schematic cross-sectional view illustrating the cross section of the surface light emitting device according to the first embodiment taken along line VII-VII in FIG. 6B. [Figure 8] 4 is a flowchart illustrating a method for manufacturing the surface light emitting device according to the first embodiment. [Figure 9A] 3 is a schematic cross-sectional view illustrating a wiring board manufactured by the method for manufacturing a wiring board according to an embodiment, in the method for manufacturing the surface light emitting device according to the first embodiment. FIG. [Figure 9B] 3 is a schematic cross-sectional view illustrating a state in which a light source is arranged in the method for manufacturing the surface light emitting device according to the first embodiment. FIG. [Figure 9C] 3 is a schematic cross-sectional view illustrating a state in which a light reflecting member is arranged in the method for manufacturing the surface light emitting device according to the first embodiment. FIG. [Figure 9D] 4 is a schematic cross-sectional view illustrating a state in which a first light guide member is arranged in the method for manufacturing the surface light emitting device according to the first embodiment. FIG. [Figure 9E] 5 is a schematic cross-sectional view illustrating a state in which a second light guide member is arranged in the method for manufacturing the surface light emitting device according to the first embodiment. FIG. [Figure 9F] 4 is a schematic cross-sectional view illustrating a state in which a light adjustment member is arranged in the method for manufacturing the surface light emitting device according to the first embodiment. FIG. [Figure 10A]10 is a schematic cross-sectional view illustrating a surface light emitting device according to a first modified example of a first light guide member. FIG. [Figure 10B] 10 is a schematic cross-sectional view illustrating a surface light emitting device according to a second modified example of a first light guide member. FIG. [Figure 10C] 10 is a schematic cross-sectional view illustrating a surface light emitting device according to a third modified example of a first light guide member. FIG. [Figure 11] 6C is a schematic cross-sectional view illustrating the cross section of the surface light-emitting device according to the second embodiment taken along line XI-XI in FIG. 6B. [Figure 12] 10 is a flowchart illustrating a method for manufacturing the surface light emitting device according to the second embodiment. [Figure 13A] 10 is a schematic cross-sectional view illustrating a wiring board manufactured by a method for manufacturing a wiring board according to an embodiment, in a method for manufacturing a surface light emitting device according to a second embodiment. FIG. [Figure 13B] 10 is a schematic cross-sectional view illustrating a state in which a light reflecting member is arranged in a method for manufacturing a surface light emitting device according to a second embodiment. FIG. [Figure 13C] 10 is a schematic cross-sectional view illustrating a state in which through holes have been formed in a method for manufacturing a surface light emitting device according to a second embodiment. FIG. [Figure 13D] 10 is a schematic cross-sectional view illustrating a state in which a light source is arranged in a method for manufacturing a surface light emitting device according to a second embodiment. FIG. [Figure 13E] 10 is a schematic cross-sectional view illustrating a state in which a connecting member is arranged in a method for manufacturing a surface light emitting device according to a second embodiment. FIG. [Figure 13F] 10 is a schematic cross-sectional view illustrating a state in which a first light guide member is arranged in a method for manufacturing a surface light emitting device according to a second embodiment. FIG. [Figure 13G] 10 is a schematic cross-sectional view illustrating a state in which a second light guide member is arranged in a method for manufacturing a surface light emitting device according to a second embodiment. FIG. [Figure 13H] 10 is a schematic cross-sectional view illustrating a state in which a light adjustment member is arranged in a method for manufacturing a surface light emitting device according to a second embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments according to the present disclosure will be described with reference to the drawings. However, the embodiments described below are intended to embody the technical ideas of the present disclosure, and unless otherwise specified, the invention is not limited to the following. The content described in one embodiment can also be applied to other embodiments and modified examples. Furthermore, the drawings are schematic illustrations of the embodiments, and for clarity of explanation, the scale, spacing, positional relationships, etc. of each component may be exaggerated, or some components may be omitted. The directions shown in each figure indicate the relative positions between components and are not intended to indicate absolute positions. In principle, the same names and symbols indicate components that are identical or of the same quality, and detailed explanations will be omitted as appropriate. Furthermore, in the embodiments, "cover" does not only refer to direct contact, but also includes indirect covering, for example, via another component.

[0014] [Wiring board] A wiring board 1 according to an embodiment will be described with reference to FIGS. 1A to 2B. FIG. 1A is a schematic perspective view of the second surface side illustrating a portion of the wiring board according to an embodiment, and FIG. 1B is a schematic perspective view of the first surface side illustrating a portion of the wiring board according to an embodiment. FIG. 1C is a schematic plan view of the second surface side illustrating a portion of the wiring board according to an embodiment, and FIG. 1D is a schematic plan view of the first surface side illustrating a portion of the wiring board according to an embodiment. FIG. 2A is a schematic plan view of the first surface side illustrating a via connection portion according to an embodiment. FIG. 2B is a schematic cross-sectional view illustrating a cross section taken along line IIB-IIB in FIG. 2A. As shown in FIGS. 1A to 1D, wiring board 1 can have electrical wiring with different patterns on both sides. The wiring on both sides is connected by via connection portion 50. Wiring made of metal member 20, which will be described later, is provided on one side of wiring board 1, and wiring made of conductive paste 40, which will be described later, is provided on the opposite side. Via connection portion 50 has bottomed holes 51, which will be described later, and connects the wiring on both sides with conductive paste 40. An example of via connection portion 50 is shown enlarged in FIG. 2A.

[0015] The wiring board 1 includes an insulating resin 10 having a first surface 10A and a second surface 10B opposite the first surface 10A, a substrate 30 including a metal member 20 disposed facing the second surface 10B of the insulating resin 10 and having an anticorrosive layer 21 formed on the surface of the second surface 10B, and a conductive paste 40 disposed on the substrate 30. The substrate 30 has a bottomed hole 51 penetrating the insulating resin 10 and having an inner bottom surface that is the surface of the metal member 20 facing the insulating resin 10. The inner bottom surface 51B of the bottomed hole 51 has a region 52 where the anticorrosive layer 21 has been removed, and the conductive paste 40 is located inside the bottomed hole 51 so as to face the region 52 where the anticorrosive layer 21 has been removed, and is disposed on the first surface 10A of the insulating resin 10 so as to form a wiring continuous with the conductive paste 40 located inside the bottomed hole 51. Next, each component of the wiring board 1 will be described.

[0016] (substrate) The substrate 30 is a plate- or sheet-like member that serves as the base of the wiring board 1. The shape of the substrate 30 in a plan view is, for example, rectangular. The shape of the substrate 30 in a plan view is not particularly limited. The substrate 30 has an insulating resin 10 and a metal member 20 that serves as wiring and is disposed facing a second surface 10B of the insulating resin 10. A conductive paste 40 that serves as wiring is disposed on a first surface 10A of the insulating resin 10. The wiring of the metal member 20 and the wiring of the conductive paste 40 are connected through a via connection portion 50 (through hole and conductive paste) that serves as wiring and is formed to penetrate the insulating resin 10. (insulating resin) The insulating resin 10 is an insulating plate- or sheet-like member that serves as a base on which a wiring pattern is formed. The insulating resin 10 has a first surface 10A and a second surface 10B opposite the first surface 10A, and is formed with a blind hole 51 that is a through-hole penetrating from the first surface 10A to the second surface 10B. Here, the insulating resin 10 is composed of two layers, a polyimide layer 11 and a resin layer 12, with the polyimide layer 11 side being the first surface 10A and the resin layer 12 side being the second surface 10B. The thickness T3 of the polyimide layer 11 is, for example, 12 μm or more and 75 μm or less, and the thickness T2 of the resin layer 12 is, for example, 5 μm or more and 20 μm or less. The material, structure, and thickness of the insulating resin 10 are not particularly limited.

[0017] (Metal parts) The metal member 20 is a conductive member that forms a predetermined wiring pattern. The material of the metal member 20 can be, for example, an elemental metal such as Ag, Al, Ni, Au, Cu, Ti, Pt, or W, or an alloy containing any of these. Here, copper foil is used as the metal member 20 as an example. The thickness T1 of the copper foil is, for example, 12 μm or more and 35 μm or less. The wiring pattern of the metal member 20 can be formed by etching. The metal member 20 can be provided with a connection pad portion 22. The connection pad portion 22 is a part of the metal member 20 that is formed, for example, with a wide width to make it easier to provide the via connection portion 50. Here, the rectangular connection pad portion 22 is provided at the tip of the wiring pattern of the metal member 20 and is arranged so as to have an area that overlaps with wiring made of a conductive paste 40, which will be described later, in a plan view. The connection pad portion 22 can be formed by etching together with the wiring pattern.

[0018] The surface of the metal member 20 is subjected to a rust-preventive treatment. In particular, a rust-preventive layer 21 is formed on the surface facing the insulating resin 10. The rust-preventive layer 21 may be, for example, a roughened layer formed by roughening the surface with irregularities, a plating layer of Zn, Ni, Cr, or the like, or an organic coating layer, forming the surface of the copper foil serving as the metal member 20. The rust-preventive layer 21 prevents oxidation of the metal member 20, such as copper foil, and improves adhesion to the insulating resin 10. However, the electrical resistance of the rust-preventive layer 21 is higher than that of the copper foil. Therefore, when electrical contacts are to be formed on the surface of the copper foil facing the insulating resin 10, it is preferable to remove the rust-preventive layer 21 to reduce the electrical resistance at the electrical contacts. The rust-preventive layer 21 can be removed by, for example, evaporation via laser irradiation, chemical reaction with a reducing agent, mechanical grinding, or other methods. The thickness of the rust-preventive layer 21 is, for example, 0.1 μm to 7 μm. The area from which the anticorrosive layer 21 is removed relative to the inner bottom surface 51B of the blind hole 51 may be 20% or more, preferably 40% or more, more preferably 55% or more, and even more preferably 70% or more. The area from which the anticorrosive layer 21 is removed relative to the inner bottom surface 51B of the blind hole 51 is preferably 80% or less. The area from which the anticorrosive layer 21 is removed relative to the inner bottom surface 51B of the blind hole 51 may be 100%. This reduces the electrical resistance between the conductive paste 40 and the metal member 20. The area from which the anticorrosive layer 21 is removed may be in one or more locations within the blind hole 51. Furthermore, the surface of the metal member 20 at the location from which the anticorrosive layer 21 is removed may be uneven. For example, fine unevenness is formed on the surface of the metal member 20 when the anticorrosive layer 21 is removed using a laser or the like. These fine unevenness can strengthen the bond between the conductive paste 40 and the metal member 20. The surface roughness (Ra) of the metal member 20 at the location where the anticorrosive layer 21 has been removed is preferably 0.1 μm to 3.0 μm, and more preferably 0.2 μm to 1.5 μm.

[0019] (Conductive paste) The conductive paste 40 forms wiring arranged on the first surface 10A and is a material that connects the wiring arranged on the first surface 10A with the metal member 20 arranged opposite to the second surface 10B. The conductive paste 40 is arranged as wiring on the first surface 10A and is also arranged in the bottomed holes 51 described below. The volume resistivity of copper foil is, for example, 1.7 μΩ·cm, while the volume resistivity of conductive paste 40 is, for example, 10 μΩ·cm or more and 100 μΩ·cm or less. To reduce the wiring resistance of conductive paste 40, the cross-sectional area of the wiring can be increased. The wiring thickness T4 of conductive paste 40 for the wiring arranged on first surface 10A is, for example, 10 μm or more and 30 μm or less to make wiring board 1 as thin as possible. For this reason, the wiring width of conductive paste 40 is preferably 0.5 mm or more and 2 mm or less. The material of the conductive paste 40 is, for example, a mixture of a resin binder with a simple substance such as gold, silver, copper, platinum, or aluminum, or an alloy or mixed powder thereof. The resin binder may be, for example, a thermosetting resin such as an epoxy resin or a silicone resin. Furthermore, the conductive paste 40 preferably contains a reducing agent such as an organic acid. This can reduce the electrical resistance in the connection with the metal member 20.

[0020] (Bottomed hole) The bottomed holes 51 are formed by penetrating the insulating resin 10 to form through holes, and are configured as bottomed holes by blocking the through holes with the metal member 20. The bottomed holes 51 are provided at positions facing the metal member 20, and the surface of the metal member 20 forms the inner bottom surface 51B of the bottomed holes 51. Here, two bottomed holes 51 are provided at positions facing one connection pad portion 22. (Area where the anti-corrosion layer has been removed) The region 52 where the anticorrosive layer 21 has been removed is a part of the inner bottom surface 51B of the blind hole 51, and is the region where the anticorrosive layer 21 of the metal member 20 has been removed. Here, the region 52 is provided in the center of the inner bottom surface 51B.

[0021] In the wiring board 1, the substrate 30 has a plurality of parallel bottomed holes 51, with the surface of the continuous metal member 20 facing the insulating resin 10 as the inner bottom surface 51B, and the conductive paste 40 in contact with each inner bottom surface 51B of the parallel bottomed holes 51 is continuous via wiring made of the conductive paste 40 arranged on the first surface 10A of the insulating resin 10. 2A, two parallel bottomed holes 51 are provided for one connection pad portion 22 formed of a continuous metal member 20. That is, the metal member 20 on the inner bottom surface 51B is continuous between the two bottomed holes 51. The conductive paste 40 that is continuous in the wiring on the first surface 10A contacts the region 52 where the anticorrosive layer 21 has been removed on each inner bottom surface 51B. Further, the conductive paste 40 has a filling portion 41 formed therein, which is disposed in the bottomed hole 51 and continues from the conductive paste 40 so as to protrude beyond a certain width in a plan view.

[0022] The wiring board 1 having the above-described configuration has a bottomed hole 51 that penetrates the insulating resin 10 and has the surface of the metal member 20 on the insulating resin 10 side as the inner bottom surface 51B, and the conductive paste 40 is positioned inside the bottomed hole 51, thereby ensuring reliable electrical connection between the conductive paste 40 and the metal member 20. The wiring board 1 has an area 52 on the inner bottom surface 51B of the bottomed hole 51 where the anti-rust layer 21 has been removed, and the conductive paste 40 is positioned inside the bottomed hole 51 so as to face the area 52 where the anti-rust layer 21 has been removed, thereby reducing the electrical resistance in the connection between the conductive paste 40 and the metal member 20. In the wiring board 1, the conductive paste 40 located inside the bottomed hole 51 and the conductive paste 40 arranged on the first surface 10A of the insulating resin 10 to form wiring are continuous, so that via filling and wiring can be performed with a single component, thereby reducing the increase in the number of component types required for the double-sided board. In the wiring board 1, the conductive paste 40 in contact with each inner bottom surface 51B of the parallel bottomed holes 51 is continuous via wiring made of the conductive paste 40 arranged on the first surface 10A of the insulating resin 10, thereby making the electrical connection between the conductive paste 40 and the metal member 20 more reliable and reducing the electrical resistance in the connection.

[0023] The shape of the connection pad portion 22 may be rectangular, trapezoidal, or a shape including a curved portion. Alternatively, the connection pad portion 22 may not be provided, and the bottomed hole 51 may be provided so that the inner bottom surface 51B is located in a part of the wiring pattern of the metal member 20. Furthermore, one or three or more blind holes 51 may be provided for one connection pad portion 22 or the wiring pattern of a continuous metal member 20. When a plurality of blind holes 51 are provided, they may be arranged in the same direction as the wiring of the conductive paste 40, as shown in Fig. 2A, or in a different direction from the wiring of the conductive paste 40. For example, as shown in Fig. 2C, the wiring of the conductive paste 40 may terminate at the position of the rectangular connection pad portion 22A, and three blind holes 51 may be arranged in different directions.

[0024] Next, a method S10 for manufacturing a wiring board according to the embodiment will be described with reference to FIGS. 3 to 5A. The method S10 for manufacturing a wiring board includes the steps of: step S1 of preparing a substrate 30 having an insulating resin 10 having a first surface 10A and a second surface 10B opposite to the first surface 10A; and a metal member 20 having an anti-rust layer 21 formed on its surface, which is arranged facing the second surface 10B of the insulating resin 10; step S3 of irradiating a first laser beam L1 from the first surface 10A side of the insulating resin 10 to penetrate the insulating resin 10 and form a bottomed hole 51 whose inner bottom surface 51B is the surface of the metal member 20 facing the insulating resin 10; step S4 of removing the anti-rust layer 21 formed on the surface of the metal member 20 at the inner bottom surface 51B of the bottomed hole 51; step S5 of injecting a conductive paste 40 into the bottomed hole 51 and applying the conductive paste 40 to the first surface 10A of the insulating resin 10 so as to form a wiring continuous with the injected conductive paste 40; and step S6 of hardening the conductive paste.

[0025] (Substrate preparation process) The substrate preparation step S1 is a step of preparing a substrate 30 in which a metal member 20 is disposed facing one surface (second surface 10B) of an insulating resin 10. The metal member 20 is, for example, copper foil, and an anticorrosive layer 21 is formed on the surface on the insulating resin 10 side. The metal member 20 is bonded to a polyimide layer 11, which serves as a base material for the insulating resin 10, via a resin layer 12, which serves as an adhesive layer. The metal member 20 and the insulating resin 10 are prepared by bonding them together in sheet form. The material, structure, and thickness of the insulating resin 10 are not particularly limited. For example, the metal member 20 and the polyimide layer 11 may be bonded together by thermocompression bonding or the like, without providing the resin layer 12. The substrate 30 may be prepared by purchasing. Alternatively, a material in which the polyimide layer 11 and the resin layer 12 are formed of polyimide resin and integrated with the insulating resin 10 may be used.

[0026] (Process for etching metal members) Step S2 of etching the metal member is a step of forming a wiring pattern on the metal member 20 by etching. Formation of the wiring pattern also includes formation of connection pad portions 22. Note that in step S1 of preparing a substrate, a substrate on which the wiring pattern of the metal member 20 has already been formed may be purchased. In this case, step S2 of etching the metal member can be omitted.

[0027] (Process for forming a bottomed hole) Step S3 of forming a blind hole is a step of forming a blind hole 51 in the insulating resin 10 by penetrating the insulating resin 10. If the blind hole 51 is small, it will be difficult to inject the conductive paste 40 in a later step. On the other hand, if the blind hole 51 is large, it will be necessary to form the metal member 20 wider, which will limit the arrangement of the wiring pattern of the metal member 20. For this reason, the maximum diameter D1 of the blind hole 51 is 50 μm or more and 800 μm or less, preferably 100 μm or more and 500 μm or less, and more preferably 200 μm or more and 300 μm or less.

[0028] In the step S3 of forming a bottomed hole, the bottomed hole 51 is formed so that the inner diameter of the bottomed hole 51 increases from the second surface 10B side toward the first surface 10A side. In other words, the bottomed hole 51 has a tapered shape that narrows toward the inner bottom surface 51B. In step S3 of forming a blind hole, blind hole 51 is formed in insulating resin 10 made of resin by irradiating first laser light L1 from the first surface 10A side. From the viewpoint of processing speed, a CO2 laser is preferable as the laser to be used, but a green laser, UV laser, or the like can also be used.

[0029] In step S3 of forming the bottomed holes, a plurality of bottomed holes 51 are formed in parallel, with the surface of the continuous metal member 20 on the insulating resin 10 side serving as the inner bottom surface 51B. Then, in step S5 of injecting and applying the conductive paste described below, the conductive paste 40 in contact with the inner bottom surfaces 51B of the plurality of bottomed holes 51 formed in parallel is made continuous via the conductive paste 40 on the first surface 10A. In this step S3, as an example, two blind holes 51 are formed in parallel at positions facing one connection pad portion 22 formed by the continuous metal member 20. The surface of the connection pad portion 22 on the insulating resin 10 side forms the inner bottom surfaces 51B of the two blind holes 51. Then, in step S5 of injecting and applying the conductive paste, the conductive paste 40 is injected and applied so that the conductive paste 40 in contact with the inner bottom surfaces 51B of the two blind holes 51 is continuous via the conductive paste 40 on the first surface 10A. Note that the blind holes 51 may be formed in any position facing the metal member 20, regardless of whether they are connection pad portions 22 or not.

[0030] (Process for removing the anti-rust layer) The anticorrosion layer removing step S4 is a step of removing the anticorrosion layer 21 from the inner bottom surface 51B of the blind hole 51. In this step S4, a second laser beam L2 having higher energy than the first laser beam L1 is irradiated onto the center of the inner bottom surface 51B of the blind hole 51. The irradiation of the second laser beam L2 forms a region 52 on the inner bottom surface 51B from which the anticorrosion layer 21 has been removed. Note that, in order to remove the anticorrosion layer 21, the second laser beam L2 having higher energy than the first laser beam L1, which is suitable for processing resin, is required. Furthermore, the temperature rise caused by the irradiation of the second laser beam L2 may melt and deform the insulating resin 10 around the inner bottom surface 51B. For this reason, it is preferable to irradiate the second laser beam L2 onto the center of the inner bottom surface 51B, which is away from the inner side surface 51A.

[0031] It is also preferable to use the same laser for irradiation of the first laser beam L1 and the second laser beam L2. Using the same laser can improve the alignment accuracy for adjusting the irradiation position on the inner bottom surface 51B of the bottomed hole 51. Furthermore, it is not necessary to change the equipment, which can improve productivity in the manufacturing process. It is also preferable to use a CO2 laser for irradiation of the first laser beam L1 and the second laser beam L2. Because the wavelength of the CO2 laser is long, it has little effect on the metal member 20, and high power, for example, an output of 200 W or more, can be irradiated for processing. This allows for efficient removal of the insulating resin 10 and the anticorrosive layer 21.

[0032] The second laser light L2 is irradiated, for example, through an opening in the mask ML. The second laser light L2 that has passed through the opening in the mask ML is focused by a lens and irradiated onto the center of the inner bottom surface 51B of the bottomed hole 51. The shape of the opening in the mask ML may be, for example, circular. The area of the inner bottom surface 51B irradiated with the second laser light L2 is preferably 20% to 60% of the area of the inner bottom surface 51B, and the maximum diameter of the area irradiated with the second laser light L2 is, for example, 20 μm to 300 μm, and preferably 50 μm to 200 μm.

[0033] (Process of injecting and applying conductive paste) The step S5 of injecting and applying the conductive paste is a step of applying the fluid unhardened conductive paste 40 to the bottomed holes 51 and the first surface 10A of the insulating resin 10. The conductive paste 40 may be applied, for example, by injection from the nozzle of a dispenser, or by screen printing, or a combination of nozzle injection and screen printing, such as by injecting from the nozzle and then screen printing.

[0034] In step S5 of injecting and applying the conductive paste, for example, the conductive paste 40 is injected and applied through the opening MA1 in the mask M1. In plan view, the overlapping area between the opening MA1 in the mask M1 and the opening of the blind hole 51 is 40% to 70% of the area of the opening of the blind hole 51, preferably 45% to 60%, and more preferably 50% to 55%. The injection and application of the conductive paste 40 can be performed by screen printing or metal mask printing using the mask M1. As shown in FIG. 5A, the opening MA1 of the mask M1 overlaps a portion of the blind hole 51 in a plan view. Note that FIG. 5A is a schematic plan view of the substrate 30 as viewed from the first surface 10A side. For example, the connection pad portion 22 of the metal member 20 is formed on the opposite surface, the second surface 10B, which serves as the inner bottom surface 51B of the blind hole 51. The conductive paste 40 is injected into the blind hole 51 from a region P11 where the opening MA1 and the blind hole 51 overlap. For example, the opening of the blind hole 51 is circular, and the region P11 has a shape obtained by removing the arc from the opening of the blind hole 51. In this step S5, the position and amount of the conductive paste 40 injected into the blind hole 51 can be adjusted by adjusting the shape and size of the region P11.

[0035] 4E, immediately after injection, inner bottom surface 51B has a portion that does not face conductive paste 40. Due to its fluidity, conductive paste 40 spreads to adhere to inner bottom surface 51B. At this time, air facing inner bottom surface 51B is pushed out by conductive paste 40 and discharged to the outside from bottomed hole 51 as air flow A3, for example.

[0036] (Process for hardening the conductive paste) The step S6 of hardening the conductive paste is a step of hardening the applied conductive paste 40. The hardening of the conductive paste 40 is carried out by, for example, heat treatment. The conductive paste 40 located inside the bottomed hole 51 faces the entire surface of the region 52 from which the anticorrosive layer 21 has been removed. This reduces the electrical resistance in the connection between the metal member 20 and the conductive paste 40. Furthermore, since the region 52 is not exposed to air, oxidation of the metal member 20 can be suppressed. The volume of conductive paste 40 located inside bottomed hole 51 is 80% or more, preferably 90% or more, and more preferably 100% of the volume of bottomed hole 51. As the volume of conductive paste 40 located inside bottomed hole 51 approaches 100% of the volume of bottomed hole 51, the wiring resistance of conductive paste 40 inside bottomed hole 51 can be reduced.

[0037] The manufacturing method S10 for a wiring board having the above-described configuration irradiates a first laser light L1 from the first surface 10A side of the insulating resin 10 to penetrate the insulating resin 10 and form a bottomed hole 51 whose inner bottom surface 51B is the surface of the metal member 20 facing the insulating resin 10, and injects conductive paste 40 into the bottomed hole 51, thereby ensuring electrical connection between the metal member 20 and the conductive paste 40.

[0038] In the method S10 for manufacturing the wiring board, the conductive paste 40 is injected into the blind holes 51, and the conductive paste 40 is applied to the first surface 10A of the insulating resin 10 so as to form wiring continuous with the injected conductive paste 40, and the conductive paste is then cured, so that the conductive paste 40 can be printed and disposed on the first surface 10A of the insulating resin 10 and the blind holes 51 all at once, for example, and wiring and via filling can be easily performed. In addition, since the conductive paste 40 is stretchable, it is less likely to break when the wiring board 1 is bent or warped, and highly reliable wiring can be obtained.

[0039] In wiring substrate manufacturing method S10, the area where opening MA1 of mask M1 and the opening of bottomed hole 51 overlap in a plan view is 45% to 60% of the area of the opening of bottomed hole 51, so that immediately after conductive paste 40 is injected through opening MA1 of mask M1, inner bottom surface 51B has a portion that does not face conductive paste 40. Then, conductive paste 40 spreads over inner bottom surface 51B while pushing out air, thereby suppressing the generation of air bubbles and improving adhesion between inner bottom surface 51B and conductive paste 40.

[0040] In the wiring board manufacturing method S10, the anticorrosion layer 21 formed on the surface of the metal member 20 is removed from the inner bottom surface 51B of the blind hole 51, thereby suppressing an increase in resistance due to the anticorrosion layer 21. If a metal member 20 without the anticorrosion layer 21 is used from the beginning, the temperature of the metal member 20 may rise due to irradiation with the first laser light L1 in the blind hole forming step S3, which may cause the surface to oxidize and increase the electrical resistance of the connection. In the wiring board manufacturing method S10, the metal member 20 with the anticorrosion layer 21 is used, and the anticorrosion layer 21 is removed before connecting with the conductive paste 40, thereby reliably reducing the electrical resistance of the connection. The metal member 20 without the anticorrosion layer 21 is, for example, a copper foil provided with only an organic coating as an anticorrosion treatment and no roughened layer or plated layer.

[0041] In the wiring substrate manufacturing method S10, the bottomed hole 51 is formed to have a tapered shape such that the inner diameter of the bottomed hole 51 increases from the second surface 10B side toward the first surface 10A side, whereby the conductive paste 40 can be injected while being in close contact with the inner surface 51A of the bottomed hole 51, thereby suppressing the generation of air bubbles. In addition, the angle formed between the first surface 10A of the insulating resin 10 and the inner surface 51A of the bottomed hole 51 is an obtuse angle, which makes it less likely that the conductive paste 40 will break. The wiring board manufacturing method S10 irradiates only the center of the inner bottom surface 51B of the bottomed hole 51 with a second laser light L2 having greater energy than the first laser light L1, thereby removing the anti-rust layer 21 while suppressing melting of the insulating resin 10 around the inner bottom surface 51B.

[0042] (Modification of removing the anti-rust layer) The anticorrosive layer 21 may be removed by irradiating the center of the inner bottom surface 51B of the blind hole 51 with a third laser beam L3 having a shorter wavelength than the first laser beam L1 in the anticorrosive layer removing step S4. The irradiation of the third laser beam L3 can be performed in the same manner as the irradiation of the second laser beam L2 described above. The third laser beam L3 has a short wavelength, which makes it possible to easily remove the anticorrosive layer 21. On the other hand, a laser beam with a short wavelength may damage the metal member 20. In such cases, the effects on the metal member 20 can be reduced by, for example, shortening the irradiation time or reducing the output.

[0043] The anticorrosive layer 21 may be removed by grinding the surface of the inner bottom surface 51B of the blind hole 51 with a needle-shaped tool. When grinding with a tool, the ratio of the area of the region 52 where the anticorrosive layer 21 has been removed to the area of the inner bottom surface 51B can be made larger than when irradiating with laser light. Furthermore, when grinding with a tool, the region 52 can be formed at a position other than the center of the inner bottom surface 51B, and may be formed over the entire surface of the inner bottom surface 51B, for example.

[0044] The anticorrosion layer 21 may be removed by adding a reducing agent to the conductive paste 40 in step S5 of injecting and applying the conductive paste. By adding a reducing agent to the conductive paste 40, the laser light irradiation and tool grinding for removing the anticorrosion layer 21 can be omitted, thereby reducing the number of steps. The anticorrosion layer 21 may be removed by any one of the laser light irradiation, tool grinding, and adding a reducing agent to the conductive paste, or by a combination of two or more of these methods.

[0045] (Modification of the mask for applying conductive paste) In step S5 of injecting and applying the conductive paste 40, the direction in which the squeegee (spatula) is moved during screen printing on the region P11 may cause variations in the amount of conductive paste 40 injected into the bottomed holes 51. In such cases, the problem can be improved by changing the shape of the region P11.

[0046] 5B, mask M2 has a substantially L-shaped region P12 where opening MA2 and bottomed hole 51 overlap. Mask M2 makes region P12 substantially L-shaped, which allows conductive paste 40 to be injected into bottomed hole 51 from two directions that form a substantially right angle. This allows conductive paste 40 to be injected into bottomed hole 51 with reduced variation in the amount.

[0047] 5C , in the mask M3, in each region facing the connection pad portion 22, the region P13 where the opening MA3 and the blind hole 51 overlap is formed as two roughly C-shaped regions in the figure, with the openings of the C-shaped regions facing each other. The mask M3 makes the region P13 roughly C-shaped, allowing the conductive paste 40 to be injected into the blind hole 51 from three directions. This allows the conductive paste 40 to be injected into the blind hole 51 while further reducing variation in the amount.

[0048] 5D, the mask M4 divides a region P14 where the opening MA4 and the blind hole 51 overlap into two substantially parallel regions in each blind hole 51. By dividing the region P14 into two substantially parallel regions using the mask M4, the conductive paste 40 can be injected into the blind hole 51 from two opposing directions. This allows the conductive paste 40 to be injected more uniformly into the blind hole 51 while reducing variation in the amount. Furthermore, the mask M4 allows fine adjustment of the amount of conductive paste 40 injected into the blind hole 51 by adjusting the spacing between the substantially parallel regions P14.

[0049] [Surface light emitting device] Next, a surface light-emitting device 1000A according to a first embodiment will be described with reference to FIGS. 6A to 7. As shown in FIGS. 6A and 6B, the surface light-emitting device 1000A is a device in which light sources 100 are arranged to emit light in a surface manner, and the brightness and on / off state of each light source 100 can be independently controlled. In the surface light-emitting device 1000A, each light source 100 is separated by a reflective layer 230 (described later), and each light source 100 serves as a cell, which is a unit for controlling brightness and on / off. FIG. 6A is a schematic plan view of the entire surface light-emitting device, and FIG. 6B is a schematic plan view illustrating an enlarged portion of the surface light-emitting device shown in FIG. 6A. FIG. 6C is a schematic plan view illustrating an example of a wiring substrate 1A, in which the light source 100 is disposed on an electrode 25A of a metal member 20. FIG. 7 is a schematic cross-sectional view illustrating a portion of the surface light-emitting device 1000A. The surface light emitting device 1000A includes the wiring board 1 already described, the light source 100 including the light emitting element 110 disposed on the electrode 25A of the metal member 20 on the wiring board 1, and a light reflecting member covering the metal member 20. 300A and a light reflecting member. 300A and a first light guide member 210 that covers the light guide member.

[0050] The wiring board 1 used has the configuration already described. Wiring of various patterns can be formed on the wiring board 1 depending on the application. The wiring board 1 used in the surface light emitting device 1000A has electrodes on which the light sources 100 are arranged and control wiring formed thereon for the surface light emitting device 1000A, and will be described as the wiring board 1A.

[0051] (light source) The light source 100 includes a light emitting element 110 having a pair of element electrodes 130, and a light-transmitting member 120 disposed on the light extraction surface side of the light emitting element 110. The light emitting element 110 includes a semiconductor laminate, and in this embodiment, a light-transmitting member 120 is disposed on the upper surface side of the semiconductor laminate, and a pair of element electrodes 130 is disposed on the lower surface side. The semiconductor laminate can have any composition depending on the desired emission wavelength. For example, a nitride semiconductor (In) capable of emitting blue or green light can be used. x Al yGa 1-x-y N, 0 ≤ X, 0 ≤ Y, X + Y ≤ 1), GaP, or GaAlAs, AlInGaP, etc. that can emit red light can be used. Also, the size and shape of the light-emitting element 110 can be appropriately selected according to the purpose of use.

[0052] The light-transmissive member 120 is made of, for example, a light-transmissive resin material, and an epoxy resin, a silicone resin, or a resin obtained by mixing these can be used. The light-transmissive member 120 may contain a phosphor. For example, by containing a phosphor that absorbs blue light from the light-emitting element 110 and emits yellow light, white light can be emitted from the light source 100. Also, the light-transmissive member 120 may contain a plurality of types of phosphors. For example, by containing a phosphor that absorbs blue light from the light-emitting element 110 and emits green light and a phosphor that emits red light, white light can also be emitted from the light source 100.

[0053] Examples of such phosphors include yttrium aluminum garnet-based phosphors (e.g., Y3(Al,Ga)5O 12 :Ce), lutetium aluminum garnet-based phosphors (e.g., Lu3(Al,Ga)5O 12 :Ce), terbium aluminum garnet-based phosphors (e.g., Tb3(Al,Ga)5O 12 :Ce), β-sialon phosphors (e.g., (Si,Al)3(O,N)4:Eu), α-sialon phosphors (e.g., Mz(Si,Al) 12 (O,N) 16 (where 0 < z ≤ 2 and M is Li, Mg, Ca, Y, and lanthanide elements excluding La and Ce)), nitride-based phosphors such as CASN-based phosphors (e.g., CaAlSiN3:Eu) or SCASN-based phosphors (e.g., (Sr,Ca)AlSiN3:Eu), fluoride-based phosphors such as KSF-based phosphors (e.g., K2SiF6:Mn), KSAF-based phosphors (e.g., K2(Si,Al)F6:Mn), or MGF-based phosphors (e.g., 3.5MgO·0.5MgF2·GeO2:Mn), or quantum dot phosphors such as perovskite, chalcopite, etc. can be used.

[0054] (Light reflecting material) The light-reflecting member 300A is a sheet-like member having light reflectivity. The light-reflecting member 300A is disposed on the second surface 10B of the insulating resin 10 of the wiring substrate 1A, and covers the metal member 20. However, in this case, the light-reflecting member 300A has an opening 350A surrounding the light source 100, and the opening 350A surrounds the periphery of the light source 100 at a distance of about 50 μm to 100 μm in a plan view. Therefore, the light-reflecting member 300A covers the metal member 20 except for a portion located inside the opening 350A. This also applies to the manufacturing method S100A of the surface light-emitting device according to the first embodiment, which will be described later.

[0055] The light reflecting member 300A preferably has high reflectance and is white in order to effectively utilize the light from the light source 100. The reflectance of the light reflecting member 300A is preferably, for example, 90% or more, and more preferably 94% or more, at the wavelength of the light emitted by the light source 100. The light reflecting member 300A may be a resin sheet containing many bubbles (e.g., a foamed resin sheet), a resin sheet containing a light diffusing material, or the like. Examples of resins that may be used for the light reflecting member 300A include thermoplastic resins such as acrylic resin, polycarbonate resin, cyclic polyolefin resin, polyethylene terephthalate resin, polyethylene naphthalate resin, and polyester resin, and thermosetting resins such as epoxy resin and silicone resin. Examples of light diffusing materials that may be used include known materials such as titanium oxide, silica, alumina, zinc oxide, and glass.

[0056] (light-guiding member) The light guide member 200 includes a first light guide member 210 that covers the light reflecting member 300A and a second light guide member 220 that covers the light source 100. The first light guide member 210 is a translucent plate-like or sheet-like member. However, in this example, the first light guide member 210 has an opening 250 that surrounds the light source 100. The opening 250 surrounds the light source 100 at a distance of approximately 100 μm to 200 μm in plan view and is large enough to enclose the opening 350A of the light reflecting member 300A at a position facing the opening 350A. Therefore, the first light guide member 210 covers the light reflecting member 300A except for a portion located inside the opening 250. This also applies to the manufacturing method S100A of the surface light-emitting device according to the first embodiment and first to third modified examples of the first light guide member, which will be described later. The second light-guiding member 220 is disposed so as to fill the opening 250 of the first light-guiding member 210 and cover the area from the opening 350A to the light source 100.

[0057] The material of the first light guide member 210 can be, for example, a thermoplastic resin such as acrylic, polycarbonate, cyclic polyolefin, polyethylene terephthalate, or polyester, or a light-transmitting material such as glass. It is particularly preferable to use polycarbonate, which is highly transparent and inexpensive. The material of the second light guide member 220 is not limited as long as it is a transparent resin, but it is preferable to use a thermosetting resin such as epoxy resin, silicone resin, or acrylic resin. The light-guiding member 200 is divided into cells by a reflective layer 230. The reflective layer 230 is provided to suppress light from passing through the light-guiding member 200 from an adjacent cell. The reflective layer 230 can be formed by adding a light diffusing material to the resin that is the material of the light-guiding member 200. Examples of the light diffusing material that can be used include titanium oxide, silica, and alumina.

[0058] (Light adjustment material) The surface light emitting device 1000A may include a light adjustment member 400. The light adjustment member 400 is a film-like or plate-like member that reflects a part of light from the light source 100 side toward the light reflecting member 300A side. The light adjustment member 400 is disposed at a position on the surface of the light guide member 200 that overlaps with the light source 100 in a plan view. The transmittance of the light adjusting member 400 with respect to the light from the light source 100 is preferably, for example, 20% to 60%, and more preferably 30% to 40%. The material of the light adjusting member 400 may be, for example, a resin material containing a light diffusing material, or a metal material. The resin material may be, for example, a silicone resin, an epoxy resin, or a mixture of these. The light diffusing material may be, for example, a known material such as titanium oxide, silica, alumina, zinc oxide, or glass. The light adjusting member 400 may be large enough to encompass the light source 100 at a position facing the light source 100 in a plan view. Although the light adjusting member 400 is circular in shape in FIG. 6B, it may also be rectangular, etc.

[0059] The surface light emitting device 1000A having the above-described configuration has a light source 100 including a light emitting element 110 arranged on an electrode 25A of a metal member 20 on a wiring substrate 1A, and has a light reflecting member 300A covering the metal member 20, thereby suppressing light absorption by the metal member 20, and has a first light guiding member 210 covering the light reflecting member 300A, thereby enabling efficient extraction of light from the light source 100. In the surface light emitting device 1000A, one light source 100 is used as one cell, which is the unit for controlling brightness and turning on / off, but the number of light sources 100 included in one cell may be one or more. For example, one cell may consist of four light sources 100 arranged in two rows and two columns, or nine light sources 100 arranged in three rows and three columns.

[0060] [Method of manufacturing a surface light emitting device] Next, a method S100A for manufacturing a surface light emitting device according to the first embodiment will be described with reference to Figures 8 to 9F. Figure 8 is a flowchart of the method S100A for manufacturing a surface light emitting device. Figures 9A to 9F are schematic cross-sectional views illustrating the method S100A for manufacturing a surface light emitting device. The method for manufacturing a surface light emitting device S100A includes step S110 of manufacturing a wiring board by the method for manufacturing a wiring board S10, step S120 of arranging light sources 100 including light emitting elements 110 on electrodes 25A of metal member 20 in wiring board 1A, step S130A of arranging light reflecting member 300A so as to cover metal member 20, and step S141 of arranging first light guide member 210 so as to cover light reflecting member 300A. The method may further include step S142 of arranging second light guide member 220 and step S150 of arranging light adjustment member 400.

[0061] (Process for manufacturing wiring boards) The wiring board manufacturing step S110 is a step of manufacturing the wiring board 1A by the wiring board manufacturing method S10. In FIG. 9A, the second surface 10B of the insulating resin 10 on which the metal member 20 is disposed is the upper surface in the figure. The spacing between the electrodes 25A can be adjusted to suit the light source 100. Here, the spacing is set to G1A so that the electrodes 25A face the pair of element electrodes 130. The wiring board 1A has a conductive paste 40 disposed thereon, but this is not shown in the cross sections in FIGS. 9A to 9F.

[0062] (Process of placing the light source) The step S120 of disposing the light source is a step of disposing the light source 100 on the wiring substrate 1A. In the method S100A for manufacturing a surface light-emitting device, the light source 100 is disposed on the electrode 25A of the metal member 20 on the wiring substrate 1A. In this step S120, the pair of element electrodes 130 are bonded to the electrode 25A via a conductive adhesive member. Examples of the conductive adhesive member that can be used include bumps made of gold, silver, copper, or the like; conductive paste, which is a mixture of metal powder such as gold, silver, copper, platinum, or aluminum with a resin binder; or tin-silver-copper (SAC) or tin-bismuth (SnBi) solder. Here, the light source 100 is disposed by solder reflow. The conductive adhesive member is disposed between the pair of element electrodes 130 and the electrode 25A.

[0063] (Step of placing a light reflecting member) The step S130A of disposing a light-reflecting member is a step of disposing a light-reflecting member 300A so as to cover the metal member 20. In this step S130A, the light-reflecting member 300A has an opening 350A formed to surround the light source 100, and is disposed so that the light source 100 is positioned within the opening 350A. Adhesive sheets with adhesive or sticky surfaces on both sides are attached to the upper and lower surfaces of the light-reflecting member 300A. The adhesive sheets are made of urethane, acrylic resin, or the like, and have a thickness of approximately 10 μm to 75 μm. Furthermore, it is desirable to add titanium oxide, barium sulfate, or the like to the adhesive sheet to improve reflectivity. A white bonding sheet can be used as the adhesive or sticky sheet, and can be layered or sandwiched with a white polyethylene terephthalate sheet to further increase reflectivity. The light-reflecting member 300A may also be disposed by applying an adhesive without using an adhesive sheet.

[0064] (Step of arranging the first light guide member) The step S141 of arranging the first light guide member is a step of arranging the first light guide member 210 so as to cover the light reflecting member 300A. In this step S141, the first light guide member 210 is a plate-like or sheet-like member in which an opening 250 is formed so as to surround the light source 100, and is arranged so that the light source 100 is located at the opening 250. In this step S141, the first light guide member 210 is aligned, and then pressed toward the wiring board 1A while being heated, to be bonded to the light reflecting member 300A. In this step S141, the first light guide member 210 has a reflective layer formed in advance at a predetermined position (see FIG. 7).

[0065] (Step of arranging the second light guide member) The method S100A for manufacturing a surface light emitting device may include a step S142 of arranging a second light guide member. The step S142 of arranging a second light guide member is a step of arranging the second light guide member 220 so as to cover the light source 100. In this step S142, the second light guide member 220 can be arranged so as to cover the light source 100 by injecting a liquid or paste-like resin from the opening 250 of the first light guide member 210 and curing it. The material of the second light guide member 220 may be the same as or different from that of the first light guide member 210. In this step S142, the same material as that of the first light guide member 210 is injected from the opening 250 in an uncured state and cured. Note that step S140 of arranging light guide members is a combination of step S141 of arranging the first light guide member and step S142 of arranging the second light guide member.

[0066] (Step of placing light adjustment member) The method S100A for manufacturing a surface light-emitting device may include a step S150 of arranging a light adjustment member. The step S150 of arranging a light adjustment member is a step of arranging the light adjustment member 400 at a position on the surface of the light guide member 200 that overlaps with the light source 100 in a planar view. In this step S150, the light adjustment member 400 may be formed by applying and curing a resin material on the light guide member 200, or a film-like or plate-like member may be disposed. In this step S150, as an example, a silicone resin containing titanium oxide is applied to a position on the surface of the light guide member 200 that faces the light source 100.

[0067] The manufacturing method S100A for a surface light emitting device having the above-described configuration reduces the manufacturing time and number of steps for the wiring board by the manufacturing method S10 for the wiring board, and by arranging the light source 100 on the electrode 25A of the metal member 20, arranging the light reflecting member 300A so as to cover the metal member 20, and arranging the first light guiding member 210 so as to cover the light reflecting member 300A, the manufacturing time and number of steps for the surface light emitting device can be further reduced.

[0068] (Modification of light guide member) Next, modified examples of the first light guide member will be described with reference to FIGS. 10A to 10C. 10A , a surface light emitting device 1001A according to a first modified example of a first light guide member has a semi-elliptical cross section of a reflective layer 231. The reflective layer 231 is preferably provided so that its cross section is widest at a position facing the light reflecting member 300A and becomes narrower toward the upper surface of the first light guide member 211. In this case, the reflective layer 231 is not provided in a position close to the upper surface of the first light guide member 211. The reflective layer 231 may be provided so that its cross section is widest at the upper surface of the first light guide member 211 and becomes narrower toward the lower surface. In this case, the reflective layer 231 is not provided in a position close to the lower surface of the first light guide member 211. In the first modified example of the first light guide member, the reflective layer 231 that separates the first light guide member 211 between adjacent light sources 100 is not provided in a position close to the upper or lower surface of the first light guide member 211, which allows part of the light to spread beyond the range separated by the reflective layer 231. This makes it possible for the first modified example to make the difference in brightness between adjacent light sources 100 less noticeable. Furthermore, in the first modified example, the width of the reflective layer 231 toward the upper or lower surface of the first light guide member 211 can be adjusted to adjust the brightness near the reflective layer 231.

[0069] 10B , in a surface light emitting device 1002A according to a second modified example of a first light guide member, the reflective layer 232 has a rectangular cross section and is provided with an equal width from the lower surface to the upper surface of the first light guide member 212. Furthermore, there is a gap 240 between the reflective layer 232 and adjacent first light guide members 212. The first light-guiding member 212 having the reflective layer 232 can be formed, for example, by cutting a first light-guiding member without a reflective layer into individual pieces of the same size so that each piece contains one light source 100, and applying the material of the reflective layer to the outer peripheral surface of the cut-out first light-guiding member. In the second modified example of the first light guide member, by having a gap 240 between adjacent reflective layers 232, there are two reflective layers 232 between adjacent light sources 100, and an air layer can be provided between the two layers. This makes it possible for the second modified example to more effectively suppress the spread of light beyond the range defined by the reflective layers 232.

[0070] In a surface light emitting device 1003A according to a third modified example of a first light guide member, which is schematically shown in FIG. 10C, the reflective layer 233 has a rectangular cross-sectional shape and is provided with an equal width from the lower surface to the upper surface of the first light guide member 213. The first light-guiding member 213 having the reflective layer 233 can be formed, for example, as in the second modified example, by cutting a first light-guiding member without a reflective layer into pieces of the same size so that each piece contains one light source 100, and fitting the cut-out first light-guiding members into the lattice of the reflective layer 233 that has been formed in a lattice shape in advance. In the third modified example of the first light guide member, the first light guide member 213 and the reflective layer 233 are formed separately, so that the first light guide member 213 and the reflective layer 233, each having a surface, face each other. This makes it possible in the third modified example to increase the reflectance at the boundary between the first light guide member 213 and the reflective layer 233, thereby suppressing the spread of light and improving the light extraction efficiency.

[0071] In the first to third modified examples of the first light guiding member, the opening 250 surrounding the light source 100 is formed in the same manner as in the first light guiding member 210. The first to third modified examples can also be similarly applied to the surface light emitting device according to the second embodiment.

[0072] Next, a surface light emitting device 1000B according to a second embodiment will be described with reference to Fig. 11. Fig. 11 is a schematic cross-sectional view illustrating a portion of the surface light emitting device 1000B. Similar to the surface light emitting device 1000A already described, the surface light emitting device 1000B is a device in which light sources 100 are arranged on a wiring substrate 1 to emit light in a surface manner. In the surface light emitting device 1000B, the first surface 10A and the second surface 10B of the wiring substrate 1 are used in an inverted manner. The surface light emitting device 1000B includes a wiring substrate 1, a light reflecting member 300B that covers the first surface 10A of the insulating resin 10 on the wiring substrate 1 and the conductive paste 40, a light source 100 including a light emitting element 110 that is arranged on the first surface 10A side of the insulating resin 10, a light guiding member 200 that covers the light source 100 and the light reflecting member 300B, and a light adjustment member 400 that is arranged in a position that overlaps the light source 100 on the surface of the light guiding member 200 in a planar view.

[0073] Here, wiring board 1 for surface light emitting device 1000B is referred to as wiring board 1B, and differences from surface light emitting device 1000A will be described. The surface light emitting device 1000B differs from the surface light emitting device 1000A in the arrangement of the light source 100 and the light reflecting member 300B and the configuration related to the connection of the light source 100. The spacing between the electrodes 25B on the wiring board 1B is greater than the spacing between the electrodes 25A on the wiring board 1A.

[0074] (Arrangement of light source and light reflecting member) In the surface light emitting device 1000B, the light source 100 and the light reflecting member 300B are disposed on the first surface 10A of the insulating resin 10 of the wiring substrate 1B. The light reflecting member 300B is disposed so as to be interposed between the light source 100 and the wiring substrate 1B. As indicated by the dashed line in Fig. 11 , the light reflecting member 300B covers the conductive paste 40 filled in the bottomed holes 51 and the conductive paste 40 disposed on the first surface 10A. The reflectance and material of the light reflecting member 300B are the same as those of the light reflecting member 300A.

[0075] (Light source connection) A pair of element electrodes 130 of the light source 100 are connected to the metal member 20 of the wiring board 1B via a connection member 600 provided to penetrate the light reflecting member 300B and the wiring board 1B. The connection member 600 extends to the surface of the metal member 20 and has a region 550 connected to the surface of the metal member 20. The light guide member 200 and the light adjustment member 400 are common to the surface light emitting device 1000A, and therefore a description thereof will be omitted.

[0076] In the surface light emitting device 1000B having the above-described configuration, the light source 100 including the light emitting element 110 is disposed on the first surface 10A of the insulating resin 10 of the wiring substrate 1B, and the light reflecting member 300B covering the first surface 10A of the insulating resin 10 and the conductive paste 40 is provided, thereby suppressing light absorption by the conductive paste 40. Furthermore, the light guide member 200 covering the light source 100 and the light reflecting member 300B is provided, thereby enabling efficient extraction of light from the light source 100. Furthermore, the light adjusting member 400 is provided at a position overlapping the light source 100 on the surface of the light guide member 200 in a plan view, thereby weakening the light directly above the light source 100 on the light extraction surface of the surface light emitting device 1000B, thereby enabling the brightness of the light extraction surface to approach uniformity.

[0077] Next, a method S100B for manufacturing a surface light emitting device according to the second embodiment will be described with reference to Fig. 12 to Fig. 13H. Fig. 12 is a flowchart of the method S100B for manufacturing a surface light emitting device. Fig. 13A to Fig. 13H are schematic cross-sectional views illustrating the method S100B for manufacturing a surface light emitting device. The method for manufacturing a surface light emitting device S100B includes the steps of: manufacturing a wiring board 1B by the method for manufacturing a wiring board S10; arranging a light reflecting member 300B in the wiring board 1B so as to cover the first surface 10A of the insulating resin 10 and the conductive paste 40; arranging a light source 100 including a light emitting element 110 on the first surface 10A side of the insulating resin 10; arranging a light guide member 200 so as to cover the light source 100 and the light reflecting member 300B; and arranging a light adjustment member 400 on the surface of the light guide member 200 at a position overlapping the light source 100 in a plan view. The method for manufacturing a surface light emitting device S100B also includes the steps of forming a through hole 510 and arranging a connecting member 600. Note that the explanation of step S140 of arranging the light guide member 200 and step S150 of arranging the light adjustment member 400 overlaps with the explanation of the method for manufacturing the surface light emitting device S100A, and therefore will be omitted.

[0078] (Process for manufacturing wiring boards) The wiring board manufacturing step S110 is a step of manufacturing the wiring board 1B by the wiring board manufacturing method S10. In FIG. 13A, the first surface 10A of the insulating resin 10 is the upper surface in the figure. Here, the spacing between the electrodes 25B is a spacing G1B that is larger than that in the wiring board 1A. The wiring board 1B has a conductive paste 40 disposed thereon, but this is not shown in the cross sections in FIGS. 13A to 13H.

[0079] (Step of placing a light reflecting member) The step S131B of arranging the light reflecting member is a step of arranging the light reflecting member 300B so as to cover the first surface 10A of the insulating resin 10 and the conductive paste 40. In this step S131B, the light reflecting member 300B does not have an opening surrounding the light source 100. In this step S131B, the light reflecting member 300B can be arranged so as to cover the entire surface of the wiring board 1B. In this step S131B, the light reflecting member 300B covers the conductive paste 40 filled in the bottomed hole 51 and the conductive paste 40 arranged on the first surface 10A at a position not shown in FIGS. 13B to 13H. Similar to the light reflecting member 300A, adhesive sheets are attached to the upper and lower surfaces of the light reflecting member 300B. The upper surface of the light reflecting member 300B in the drawing is adhesive. This adhesiveness allows the pair of element electrodes 130 to be held and the light source 100 to be fixed in place in step S121B of arranging the light source, which will be described later. The light reflecting member 300B may be arranged by applying an adhesive agent without using an adhesive sheet. After bonding, the light reflecting member 300B is heated and pressed toward the wiring board 1B. This allows the upper surface of the light reflecting member 300B, which does not face the wiring board 1B, to become fluid, facilitating the subsequent steps of drilling holes and arranging the light source.

[0080] (Process for forming through holes) The step S132B of forming a through hole is a step of forming a through hole 510 that penetrates the light reflecting member 300B and the wiring substrate 1B. In this step S132B, the through hole 510 is formed by penetrating the light reflecting member 300B and the insulating resin 10 at a position facing a pair of element electrodes 130 of the light source 100 that will be arranged in a later step. The electrode 25B is positioned so as to contact the opening of the through hole 510 on the second surface 10B side of the insulating resin 10. In step S132B of forming a through hole, the through hole 510 may be formed from the light reflecting member 300B side or from the second surface 10B side of the insulating resin 10. The through hole 510 can be formed by laser processing or drilling.

[0081] (Process of placing the light source) The step S121B of arranging a light source is a step of arranging the light source 100 in the light reflecting member 300B. In this step S121B, the light source 100 is arranged so that the pair of element electrodes 130 face the through holes 510. In this step S121B, the gap G1B can be, for example, the gap separated by the two through holes 510. As described above, the upper surface of the light reflecting member 300B in the drawing has adhesiveness, and can fix the light source 100 until it is connected by the connecting member 600 in the step S122B of arranging a connecting member.

[0082] (Step of placing the connecting member) The step S122B of arranging the connecting member is a step of filling the through-hole 510 with the connecting member 600 and arranging it on the surface of the electrode 25B. In this step S122B, the connecting member 600 is filled in the through-hole 510 and connects the pair of element electrodes 130 and the electrode 25B. In step S122B of arranging the connecting member, the connecting member 600 is arranged so as to fill the through-hole 510 and then extend onto the surface of the electrode 25B. In step S122B of arranging the connecting member, the connecting member 600 has an area 550 that connects with the surface of the electrode 25B, thereby ensuring a reliable electrical connection. The connecting member 600 may be made of the same material as the conductive paste 40 or solder.

[0083] The manufacturing method S100B for a surface light emitting device having the above-described configuration can reduce the manufacturing time and number of steps for the wiring board by the manufacturing method S10 for the wiring board. Furthermore, by arranging the light reflecting member 300B so as to cover the first surface 10A of the insulating resin 10 and the conductive paste 40, and arranging the light source 100 on the first surface 10A side of the insulating resin 10, the light reflecting member 300B can be arranged closer to the light source 100, thereby improving the light extraction efficiency. Furthermore, the manufacturing method S100B for a surface light emitting device arranges the light guide member 200 so as to cover the light source 100 and the light reflecting member 300B, and arranges the light adjustment member 400 at a position on the surface of the light guide member 200 that overlaps with the light source 100 in a planar view, thereby further reducing the manufacturing time and number of steps for the surface light emitting device while suppressing an increase in the number of components. [Explanation of symbols]

[0084] 1. Wiring board 1A Wiring board (surface light emitting device of the first embodiment) 1B Wiring board (surface light emitting device of second embodiment) 10. Insulating resin 10A 1st side 10B 2nd side 11 Polyimide layer 12 Resin layer 20 Metallic parts 21 Anti-rust layer 22 Connection pad section 30 boards 40 Conductive Paste 50 via connection 51 Bottomed hole 51A Inner side 51B Inner bottom surface 52 area (area where anti-corrosion layer has been removed) 100 light sources 110 Light-emitting element 120 Translucent material 130 Element electrode 200 Light guide member 210 First light guide member 220 Second light guide member 250 opening (first light guide member) 300A Light reflecting material 300B Light reflecting member 350A Opening (light reflecting material) 400 Light adjustment material 600 Connecting member 1000A surface light emitting device 1000B Surface Light Emitting Device

Claims

1. preparing a substrate including an insulating resin having a first surface and a second surface opposite to the first surface, and a metal member having an anticorrosive layer formed on a surface thereof, the metal member being disposed opposite to the second surface of the insulating resin; a step of irradiating the insulating resin with a first laser beam from the first surface side to form a hole that penetrates the insulating resin and has an inner bottom surface on the surface of the metal member facing the insulating resin; removing the rust-preventive layer formed on the surface of the metal member at the inner bottom surface of the blind hole; injecting a conductive paste into the blind hole and applying the conductive paste to the first surface of the insulating resin so as to form a wiring continuous with the injected conductive paste; and hardening the conductive paste. In the step of removing the anticorrosive layer, a second laser beam is irradiated to remove the anticorrosive layer, thereby forming a plurality of irregularities on the surface of the metal member.

2. 2. The method for manufacturing a wiring board according to claim 1, wherein in the step of removing the anticorrosive layer, the surface roughness (Ra) of the metal member at the location where the anticorrosive layer has been removed is 0.1 [mu]m or more and 3.0 [mu]m or less.

3. 3. The method for manufacturing a wiring board according to claim 1, wherein in the step of removing the anticorrosive layer, an area from which the anticorrosive layer is removed is 20% or more of the area of the inner bottom surface of the blind hole.

4. 4. The method for manufacturing a wiring board according to claim 1, wherein in the step of removing the anticorrosion layer, the area from which the anticorrosion layer is removed is 80% or less of the inner bottom surface of the blind hole.

5. 5. The method for manufacturing a wiring substrate according to claim 1, wherein the step of removing the anticorrosive layer includes irradiating the second laser light onto a center of the inner bottom surface of the blind hole.

6. 6. The method for manufacturing a wiring substrate according to claim 1, wherein in the step of removing the anticorrosive layer, the second laser light has energy greater than that of the first laser light.

7. 7. The method for manufacturing a wiring substrate according to claim 1, wherein in the step of removing the anticorrosive layer, the second laser light is emitted using the same laser as the first laser light.

8. 8. A method for manufacturing a wiring substrate according to claim 1, wherein in the process of removing the anti-rust layer, a third laser light having a shorter wavelength than the first laser light is irradiated onto the center of the inner bottom surface of the bottomed hole.

9. In the step of removing the anticorrosive layer, the laser for irradiating the second laser beam is a CO ２ 9. The method for manufacturing a wiring board according to claim 1, wherein the laser is at least one of a laser, a green laser, and a UV laser.

10. 10. The method for manufacturing a wiring substrate according to claim 1, wherein the step of removing the anticorrosive layer further comprises removing the anticorrosive layer by a chemical reaction using a reducing agent.

11. 11. The method for manufacturing a wiring board according to claim 1, wherein in the step of preparing the substrate, the metal member is a copper foil.

12. The method for manufacturing a wiring board according to claim 11, wherein in the step of preparing the substrate, the copper foil has a thickness of 12 μm or more and 35 μm or less.

13. 13. The method for manufacturing a wiring substrate according to claim 1, wherein in the step of forming the blind holes, the blind holes have a maximum diameter of 50 [mu]m or more and 800 [mu]m or less.

14. 14. The method for manufacturing a wiring substrate according to claim 1, wherein in the step of forming the blind hole, the blind hole has a tapered shape tapering toward the inner bottom surface.

15. In the step of hardening the conductive paste, the conductive paste located inside the blind hole faces the entire surface of the region from which the anticorrosive layer has been removed, 15. The method for manufacturing a wiring substrate according to claim 1, wherein a volume of the conductive paste located inside the blind hole is 80% or more of a volume of the blind hole.

16. a step of manufacturing a wiring board by the method for manufacturing a wiring board according to any one of claims 1 to 15; a step of arranging a light source including a light emitting element on the metal member of the wiring board; a step of disposing a light reflecting member so as to cover the metal member; and a step of disposing a first light guide member so as to cover the light reflecting member.

17. a step of manufacturing a wiring board by the method for manufacturing a wiring board according to any one of claims 1 to 15; a step of disposing a light reflecting member so as to cover the first surface of the insulating resin and the conductive paste of the wiring substrate; a step of arranging a light source including a light emitting element on the first surface side of the insulating resin; a step of arranging a light guide member so as to cover the light source and the light reflecting member; and arranging a light adjustment member at a position on the surface of the light guide member that overlaps with the light source in a plan view.

18. a substrate including an insulating resin having a first surface and a second surface opposite to the first surface, and a metal member disposed opposite to the second surface of the insulating resin and having an anticorrosive layer formed on the surface of the second surface; a conductive paste disposed on the substrate; the substrate has a bottomed hole that penetrates the insulating resin and has an inner bottom surface that is a surface of the metal member that faces the insulating resin, the inner bottom surface of the blind hole has a region where the anticorrosive layer has been removed, a plurality of projections and depressions are provided on the surface of the metal member in the region where the anticorrosive layer is removed; the conductive paste is located inside the blind hole so as to face the area where the anticorrosive layer has been removed, A wiring board, wherein the area of the region where the anticorrosive layer is removed is 80% or less of the area of the inner bottom surface of the blind hole.

19. 19. The wiring board according to claim 18, wherein the surface roughness (Ra) of the metal member in the area where the anticorrosive layer has been removed is 0.1 μm or more and 3.0 μm or less.

20. 20. The wiring board according to claim 18, wherein the area of the region where the anticorrosive layer is removed is 20% or more of the area of the inner bottom surface of the blind hole.

21. 21. The wiring board according to claim 18, wherein the plurality of projections and recesses are provided at a center of the inner bottom surface of the blind hole.

22. 22. The wiring board according to claim 18, wherein the metal member is a copper foil.

23. 23. The wiring board according to claim 22, wherein the copper foil has a thickness of 12 μm or more and 35 μm or less.

24. 24. The wiring board according to claim 18, wherein the maximum diameter of the blind hole is 50 μm or more and 800 μm or less.

25. 25. The wiring board according to claim 18, wherein the bottomed hole is tapered toward the inner bottom surface.

26. the conductive paste located inside the blind hole faces the entire surface of the region where the anticorrosive layer has been removed, 26. The wiring board according to claim 18, wherein a volume of the conductive paste located inside the blind hole is 80% or more of a volume of the blind hole.

27. a wiring substrate according to any one of claims 18 to 26; a light source including a light emitting element disposed on the metal member of the wiring board; a light reflecting member covering the metal member; a first light guide member covering the light reflecting member.

28. a wiring substrate according to any one of claims 18 to 26; a light reflecting member covering the first surface of the insulating resin and the conductive paste in the wiring substrate; a light source including a light emitting element disposed on the first surface side of the insulating resin; a light guide member covering the light source and the light reflecting member; a light adjusting member disposed on the surface of the light guiding member at a position overlapping with the light source in a plan view.

Images